A chiral material with a new phase sequence: Twist grain boundary smectic A phase—blue phases

Abstract

Abstract A new phase sequence: twist grain boundary Sa phase to blue phases was observed in a chiral compound (R)- or (S)-1-methylheptyl 3′-fluoro-4′-(3″-fluoro-4″-octadecyloxybenzoyloxy)tolan-4-carboxylate. It is the first time that blue phases have been found to occur above the TGBA phase in the absence of a cholesteric phase. These phases were characterized by microscopic observation, differential scanning calorimetry, the contact method and study of the racemic system.